A question for Mike Gideon

[Guest Lester Weevils]

Hi Mike

I wonder if you have time to run a couple of recipes thru quickload to see if quickload "takes into account" any difference--

The same identical params except for primer--

9mm load, 124gn Rainier plated round nose bullet, 1.160 OAL, 5.5gn Ramshot Silhouette powder. 5" barrel if it matters. If quickload doesn't have Rainier data, the Ramshot data gives same max load and OAL for Berry's plated 124gn round nose as well, so a Berry would do just as good in the test.

Am curious if quickload gives different results whether you specify Win WSP primer versus Federal #100 small pistol primer?

Did some googling and "internet legend" says the Win small pistol primer has a "hotter spark" than Federal, and Federal are more sensitive and easier to set off. Found one fella who loaded identical loads using both Win and Federal primers and claimed to get statistically significant higher velocities from the Win primers.

But am curious if there is more than internet legend involved. According to Ramshot data, the above recipe is well below max using a Federal small pistol primer, but trying to decide whether I want to reduce the load for first-test with Win WSP primers. The Ramshot data for Max with a Federal primer is 5.8gn, so there should be some safety margin in there even if the Win primer is hotter. Just curious what quickload has to say about it. Or maybe quickload doesn't consider primer params, dunno.

Thanks if you get time to check that.

[mikegideon]

Quickload doesn't do it.

[Guest Lester Weevils]

Quickload doesn't do it.

Thanks Mike

Is it because there is no listing for a powder, bullet, or primer in the proposed recipe, or am I misunderstanding how quickload operates?

My question was too specific anyway. The exact details of powder or bullet don't matter, though a 9mm luger spec might be of interest. Maybe small pistol primers would act a little different in a bigger case like .357 or whatever.

Was just curious if quickload will let you specify a Win WSP primer versus Federal #100 small pistol primer, with all other details of a load kept constant? And if so, whether quickload calculates different pressure and velocity according to the brand of primer? Thanks.

Edited June 4, 2012 by Lester Weevils

[mikegideon]

There is a cartridge database with dimensions and max pressure, a bullet database with dimensions, weights, and shot start pressures, and a powder database. The databases are real comprehensive. There is no primer database, probably because the differences in primers are outside the accuracy of the program.

You can adjust barrel length. Like any other program, accuracy depends on the quality of the data, and the mathmatical model. You don't want quickload to be the final word, because it can be way off. it can also be real close. It shines in areas where most other simulators shine. It does a great job of showing the effects of manipulating your loads, and can be tweaked to agree more closely with real world loads. I usually try to compare it with pressure tested load data from the manufacturers. The truth is somewhere in all of it, with my chrony being the most reliable source of data.

I use SPICE in analog circuit design. It's a real powerful tool if you know its limitations. If you don't, it will get you into a bunch of trouble.

[Guest Lester Weevils]

Thanks for the excellent explanation Mike. Will probably reduce a test load a couple tenths of a gn for initial test of the win primers, just in case they are noticeably hotter, and chrony the differences. Had read some opinions that a hotter primer can have maybe more effect on slower powders than fast powders, causing em to burn unexpectedly fast and spiking pressure. Wheras the fast powders burn fast regardless. But other folks report not noticing much difference between the primers, except Federals are more sensitive and easier to set off with a "weakly sprung" trigger. One guy who claimed to have A-B tested with chrony, IIRC he reported velocity around 1120 fps with federal primer and 1170 with win primer, which isn't a huge difference but hardly negligible either.

Modeling is interesting stuff. Wish I'd paid more attention in math class and taken some EE courses. Haven't used spice but studied a bit of the open source spice code a few years ago to learn how they were modeling transformers. Was working on guitar amp emulator code and a transformer acts pretty complicated in the real world just to be a hunk of iron and wire. That, and the interaction of transformer with the speaker coil/cone, acoustic interaction of the speaker and cab "pushing back and affecting" the behavior of the transformer, all of it pushing back on the power tubes and affecting the tubes' dynamic behavior. Real complicated behavior for simple circuits. Was feeding test signals into a real guitar amp, looking at it on a scope and rta, wondering "how the heck is it doing THAT?" at various unexpected things it would do. Shoulda paid more attention in math class.

[mikegideon]

When you get down to primer tweaks, you probably need to test the loads.

When it comes to audio, you have to measure a lot of it. Spice is almost useless for most types distortion, mainly because you need lots of resolution, and the models generally aren't good enough.